Charge-Coupled Devices (CCDs) have been widely known as solid-state imaging devices for taking images of incident light, and among the CCDs, an EM-CCD (Electron Multiplying-CCD) that enables taking an image of weak light has been known. This type of solid-state imaging device includes, in addition to an imaging area that includes a plurality of photodiodes or the like and generates charges according to the amount of incident light and an output register unit that reads out the charges of the imaging area, a multiplication register unit that multiplies the read-out charges, and enables taking an image of weak light by using a charge multiplication effect of the multiplication register unit. This type of solid-state imaging device has been disclosed in Patent Literatures 1 to 3.
The solid-state imaging devices described in Patent Literatures 1 and 2 control the multiplication factor (gain) of the multiplication register unit based on an output of the multiplication register unit. Moreover, the solid-state imaging device described in Patent Literature 3 further includes an additional register unit, and increases the dynamic range by using the additional register unit for an excess charge of the multiplication register unit.